The invention relates to a cable lug comprising a receiving section for a cable and an attachment nut.
In conventional cable lugs, a plane surface of the cable lug is forced by the attachment nut against a counter surface to be contacted. The force exerted by the attachment nut generates point contacts between cable lug and counter surface. The position of the point contacts and the pressure in the resulting contact areas are rather random and undefined, since they depend on the microscopic unevenness of the cable lug and the counter surface. In this connection, it is problematic that a specific minimum pressure must be observed between counter surface and cable lug to prevent the occurrence of corrosion at the contact points.
The object of the invention consists in further developing a cable lug of the initially mentioned type such that a defined contact surface and a defined contact pressure are ensured between this contact surface and the counter surface.
To this end, a contact section is provided at the contact lug, which is provided with a bead which by means of the attachment nut can be forced against a counter surface to be contacted. The bead forms an accurately defined contact surface which abuts against the counter surface. Since the dimensions of the contact surface are known, the operative contact pressure can also be adjusted by means of the contact force exerted by the contact nut such that corrosion phenomena cannot occur.
The bead is preferably annular and concentric with respect to the center axis of the attachment nut. This ensures a symmetrical, constant contact pressure between bead and counter surface. As an alternative, an oval or similar shape is also conceivable for the bead.
According to an alternative embodiment the bead is designed discontinuously. In this way, it acts additionally as a protection against rotation when it contacts the counter surface to be contacted.
According to the preferred embodiment it is provided that the bead has a contact surface facing the counter surface to be contacted. This contact surface extends in curved manner in a cross-section along a plane containing the center axis of the attachment nut. In this way, a line contact is initially obtained when the cable lug is put on the counter surface. Thus, already when the tightening of the attachment nut starts it is possible to locally obtain contact pressures which in the case of a possible unevenness are high enough to deform the material either plastically or elastically whereby a uniform contact between contact lug and counter surface is obtained.
According to the preferred embodiment of the invention it is provided that the bead is disposed radially outside the area within which the attachment nut abuts against the contact section. With this design, the contact section is biased like a Belleville spring when the attachment nut is tightened. This ensures that the contact pressure remains almost constant also over relatively long periods of time and in the case of possible settling actions.
The bead is preferably formed by embossing the contact section on its side facing away from the counter surface. This enables cost-effective production.
Advantageous embodiments of the invention follow from the subclaims.